1999ApJ...513..142M

We model the effects of repeated supernova (SN) explosions from starbursts in dwarf galaxies on the interstellar medium of these galaxies, taking into account the gravitational potential of their dominant dark matter halos. We explore SN rates from one every 30,000 yr to one every 3 Myr, equivalent to steady mechanical luminosities of L=0.1-10x10³⁸ ergs.s^–1, occurring in dwarf galaxies with gas masses M_g=10⁶-10⁹ M_☉. We address in detail, both analytically and numerically, the following three questions:

• (1.) When do the SN ejecta blow out of the disk of the galaxy?
• (2.) When blowout occurs, what fraction of the interstellar gas is blown away, escaping the potential of the galactic halo?
• (3.) What happens to the metals ejected from the massive stars of the starburst? Are they retained or blown away?

We give quantitative results for when blowout will or will not occur in galaxies with 10⁶ M_☉≤M_g≤10⁹ M_☉. Surprisingly, we find that the mass ejection efficiency is very low for galaxies with mass M_g≥10⁷ M_☉. Only galaxies with M_g≲10⁶ M_☉ have their interstellar gas blown away, and then virtually independently of L. On the other hand, metals from the SN ejecta are accelerated to velocities larger than the escape speed from the galaxy far more easily than the gas. We find that for L₃₈=1, only about 30% of the metals are retained by a 10⁹ M_☉ galaxy, and virtually none by smaller galaxies. We discuss the implications of our results for the evolution, metallicity, and observational properties of dwarf galaxies.